Colored dissolved organic matter (CDOM), a significant fraction of dissolved organic carbon (DOC), plays various roles in physical and biogeochemical processes in natural waters. In the Arctic Ocean, CDOM is abundant because of major input by large rivers. To better understand the processes that drive variations in CDOM, light absorption coefficients of CDOM [aCDOM(λ), m-1] were extensively documented together with temperature, salinity, chlorophyll a, nitrate concentrations, and bacterial production (BP) and abundance (BA) in the Western Arctic Ocean (WAO) from early to late summer as part of the MALINA and the ICESCAPE expeditions. The data set covered contrasting situations, from bloom to post-bloom conditions and from river-influenced to oceanic water masses. While CDOM photobleaching occurred in the surface layer (<20m), we observed significantly lower spectral slopes for CDOM absorption spectra (SCDOM) in addition to higher aCDOM(440) in the layer below (intermediate layer: 30.7

This study was conducted as part of the MALINA Scientific Program funded by ANR (Agence nationale de la recherche), INSU-CNRS (Institut national des sciences de l’univers—Centre national de la recherche scientifique), CNES (Centre national d’études spatiales) and ESA (European Space Agency). This research was also supported by the Ocean Biology and Biogeochemistry Program and the Cryosphere Science Program of the National Aeronautic and Space Administration (NNX10AF42G to K. Arrigo). We also thank a joint contribution to the research programs of UMI Takuvik, ArcticNet (Network Centres of Excellence of Canada) and the Canada Excellence Research Chair in Remote Sensing of Canada’s New Arctic Frontier

Special issue More from NASA’s ICESCAPE (Impacts of Climate on EcoSystems and Chemistry of the Arctic Pacific Environment) program, Part 1.-- 9 pages, 7 figures, 2 tables

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